* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    width: 100%;
    max-width: 640px;
    min-width: 320px;
    margin: 0 auto;
    background-color: #fff;
    font-size: 14px;
    font-family: -apple-system, Helvetica, sans-serif;
    line-height: 1.5;
    color: #666;
}

li {
    list-style: none;
    float: left;
}


/* 顶部 */

.app {
    height: 45px;
    background-color: #333333;
    line-height: 45px;
    text-align: center;
}

.app ul li:nth-child(1) {
    width: 8%;
}

.app ul li:nth-child(1) img {
    width: 10px;
}

.app ul li:nth-child(2) {
    width: 10%;
}

.app ul li:nth-child(2) img {
    width: 30px;
    vertical-align: middle;
}

.app ul li:nth-child(3) {
    width: 57%;
    color: #fff;
}

.app ul li:nth-child(4) {
    width: 25%;
    color: #fff;
    background-color: #F63515;
}

.app ul li:nth-child(4) a {
    color: #fff;
    text-decoration: none;
}


/* 搜索框 */

.search {
    position: fixed;
    width: 100%;
    max-width: 640px;
    min-width: 320px;
    height: 44px;
    line-height: 44px;
    text-align: center;
    overflow: hidden;
}

.search_left {
    position: absolute;
    width: 40px;
    height: 44px;
}

.search_left::before {
    content: '';
    display: block;
    width: 20px;
    height: 18px;
    background: url(../img/s-btn.png) no-repeat;
    background-size: 20px 18px;
    margin: 12px 0 0 12px;
}

.search_right {
    position: absolute;
    top: 0;
    right: 0;
    color: #fff;
    width: 40px;
    height: 44px;
}

.search_middle {
    position: relative;
    height: 30px;
    border-radius: 15px;
    margin: 8px 50px 0;
    background-color: #fff;
}

.jd {
    position: absolute;
    top: 7px;
    left: 15px;
    width: 20px;
    height: 15px;
    background: url(../img/jd.png) no-repeat;
    background-size: 20px 15px;
}

.jd::before {
    position: absolute;
    left: 30px;
    content: '';
    display: block;
    width: 1px;
    height: 18px;
    background-color: #ccc;
}

.sou {
    position: absolute;
    top: 8px;
    left: 55px;
    width: 18px;
    height: 15px;
    background: url(../img/jd-sprites.png) no-repeat -81px 0;
    background-size: 200px auto;
}


/* 轮播图 */

.banner img {
    width: 100%;
}


/* 小品牌超级品类日 */

.ad {
    height: 150px;
}

.ad div {
    width: 33.3%;
    height: 100%;
    float: left;
}

.ad img {
    width: 100%;
    height: 100%;
}


/* 导航栏部分 */

.navigation {
    margin-top: 15px;
}

.navigation div {
    width: 20%;
    float: left;
    text-align: center;
}

.navigation img {
    width: 40px;
    margin-bottom: 5px;
}


/* 新闻模块 */

.news div {
    float: left;
    margin-top: 15px;
}

.news img {
    width: 100%;
}

.news div:first-child {
    width: 50%;
}

.news div:nth-child(n+2) {
    width: 25%;
}

.news div:nth-child(-n+2) {
    border-right: 1px solid #ccc;
}